[NFC] Pre-calculate SCC IR counts in size remarks.

Same vein as the previous commits. Pre-calculate the size of
the module and use that to decide if we're going to emit a
remark.

This one comes with a FIXME and TODO. First off, CallGraphSCC
and CallGraphNode don't have a getInstructionCount function. So,
for now, we do the same thing as in a module pass.

Second off, we're not really saving anything here yet, because
as before, I need to change emitInstrCountChangedRemark to take
in a delta. Keeping the patches small though, so that's coming up
next.

5/6

llvm-svn: 341249

1 files changed, 13 insertions, 5 deletions

diff --git a/llvm/lib/Analysis/CallGraphSCCPass.cpp b/llvm/lib/Analysis/CallGraphSCCPass.cpp
index df652552bd6..d090b5afd2e 100644
--- a/llvm/lib/Analysis/CallGraphSCCPass.cpp
+++ b/llvm/lib/Analysis/CallGraphSCCPass.cpp
@@ -131,17 +131,25 @@ bool CGPassManager::RunPassOnSCC(Pass *P, CallGraphSCC &CurSCC,
     }
 
     {
-      unsigned InstrCount = 0;
+      unsigned InstrCount, SCCCount = 0;
       bool EmitICRemark = M.shouldEmitInstrCountChangedRemark();
       TimeRegion PassTimer(getPassTimer(CGSP));
       if (EmitICRemark)
         InstrCount = initSizeRemarkInfo(M);
       Changed = CGSP->runOnSCC(CurSCC);
 
-      // If the pass modified the module, it may have modified the instruction
-      // count of the module. Try emitting a remark.
-      if (EmitICRemark)
-        emitInstrCountChangedRemark(P, M, InstrCount);
+      if (EmitICRemark) {
+        // FIXME: Add getInstructionCount to CallGraphSCC.
+        // TODO: emitInstrCountChangedRemark should take in the delta between
+        // SCCount and InstrCount.
+        SCCCount = M.getInstructionCount();
+        // Is there a difference in the number of instructions in the module?
+        if (SCCCount != InstrCount) {
+          // Yep. Emit a remark and update InstrCount.
+          emitInstrCountChangedRemark(P, M, InstrCount);
+          InstrCount = SCCCount;
+        }
+      }
     }
 
     // After the CGSCCPass is done, when assertions are enabled, use